A processor consumes far less energy running tasks requiring a low supply voltage than it does executing high-performance tasks. Effective voltage-scheduling techniques take advantage of this situation by using software to dynamically vary supply voltages, thereby minimizing energy consumption and accommodating timing constraints.
Citation:
Takanori Okuma, Hiroto Yasuura, Tohru Ishihara, "Software Energy Reduction Techniques for Variable-Voltage Processors," IEEE Design and Test of Computers, vol. 18, no. 2, pp. 31-41, Mar./Apr. 2001, doi:10.1109/54.914613